M3.9 Earthquake 72 km S of Sand Point, Alaska — July 22, 2020
2020-07-22 23:09:18 UTC (2020-07-22) · approx. 12:09 PM UTC-11 local
On July 22, 2020 at 23:09 UTC, a magnitude 3.9 shallow crustal earthquake struck 72 km S of Sand Point, Alaska, at a depth of 45.7 km and coordinates 54.6893°, -160.3237°.
Physical scale: An earthquake of magnitude 3.9 releases seismic energy equivalent to roughly 11 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 296 m — a useful intuition for the size of the slip patch on the fault.
Earthquake Details
-160.3237°E
Technical Information
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Common Questions
How strong was the magnitude 3.9 earthquake near Sand Point, Alaska?
The magnitude 3.9 earthquake that struck 72 km S of Sand Point, Alaska on July 22, 2020 at 23:09 UTC had a depth of 45.7 km. For context, this was a minor earthquake typically detected only by instruments.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 3.9 earthquakes can continue for several days and gradually diminish over time.
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Understanding This Data
Magnitude 3.9 earthquakes are typically only recorded by instruments.
Authoritative source: USGS event page (event ID: us6000b2b4). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2020, July 22, 2020). M3.9 Earthquake 72 km S of Sand Point, Alaska — July 22, 2020. Retrieved October 3, 2020 from https://www.earthquaketracker.org/earthquakes/event/us6000b2b4/